answer() opened a fresh forward waiter but, unlike send(), never
registered it in asyncTasksByWaiter. So when a worker chained a
second fleet_ask inside the same resumed turn (before calling
fleet_reply), markAsyncQuestion had no Task to re-associate, and
answer() then completed the async ticket's future with the second
QUESTION as if it were a terminal reply — fleet_poll reported FAILED
while the worker was still alive and mid-conversation.
Fix: register answer()'s waiter in asyncTasksByWaiter (mirroring
send()) so a chained ask can re-arm the ticket under its new turnId,
and guard answer()'s finishAsyncTask call the same way sendAsync's
own lambda already does (skip on Outcome.QUESTION). Also drop the
stale asyncTasksByTurn entry left behind when markAsyncQuestion
re-arms a task under a new turnId, a leak the fix makes reachable
for the first time.
Reachability confirmed by driving the exact sequence through the
public API (sendAsync -> ask -> answer -> ask again) in a new test;
reverting the production change makes it fail with
"expected: <ASKING> but was: <FAILED>", confirming it catches the
regression.
Dai Ha
6ed70700a0